Research On Silicon Photonic Crystal And Its Application In Microwave Photonics

Due to the era of Internet and Big-data approaching,the human society’s requirements toward the capacity and transfer rate of the information experience an explosive increase in recent years.As a common information carrier in both civil and military area,the frequency of the microwave is expanding to the high frequency domain,which makes the conventional electronic devices difficult to generate and process the microwave signal effectively.Therefore,the microwave photonics,which is the science of applying photonics method to the microwave region,is attracting more and more attention due to its advantages including huge bandwidth,immunity to the electromagnetic interference and low transfer loss.Considering the trend of integrating discrete fiber optics devices into a single chip in recent years,how to complete the microwave photonics function with high quality,high speed and low power consumption on chip-size silicon processor remains to be an important issue which is worth further investigation.Based on these backgrounds,the research in this dissertation will focus on the application of silicon photonic crystal in solving several crucial problems in the microwave photonics.The main contributions of this dissertation can be summarized as below:1)The slow-light enhanced high performance graphene microheater is proposed and experimentally demonstrated.By optimizing the structural parameters of the photonic crystal waveguide,the group velocity of light is decreased.Meanwhile,the conventional metallic heater is replaced by the graphene.Both the slow light effect and graphene heater contributes to the enhancement of light-matter interaction,which increases the thermal tuning efficiency and lowers the response time simultaneously.The proposed structure realizes the fastest microheater in silicon photonics,to the best of our knowledge.Besides,the influence of the shape of the microheater on the performance of the microheater is also analyzed and experimentally verified.2)The operation bandwidth limitation of photonic differentiator is proposed theoretically and experimentally demonstrated using the silicon photonic crystal.Moreover,the novel silicon photonic crystal Mach-Zehnder Interferometer is used to break the operation bandwidth bottleneck and expand the practical bandwidth of the photonic differentiator.3)The slow light effect in photonic crystal waveguide is employed to realize linear chirped microwave waveform generation within the ultra-compact footprint.By integrating two photonic crystal waveguides with different lengths into a Mach-Zehnder Interferometer structure,the frequency spectrum with the chirped free spectrum range is obtained.The linear chirped microwave waveform can be realized using the frequency to time mapping method.By altering the structural parameters of the photonic crystal waveguides,the influence of the slow light effect on the generated waveform is investigated and different types of chirp signal is realized.The possible method to realize larger time-bandwidth product is also proposed.